Valve will name the next round of games to be approved via community ratings portal Steam Greenlight on 15th October.
At least 10 more titles will be picked, Valve said in a statement on the official Steam blog, doubling the company's first selection of successful projects.
Games that are accepted - given the green light - are not automatically added to the service. Their developers are simply contacted by Valve to make sure the projects are published as soon as possible.
We had a quick look back over the initial batch of Greenlight games chosen by Valve to join Steam. Some, like Half-Life mods Black Mesa and Cry of Fear, plus retro sim Towns, remain downloadable elsewhere but not yet via Steam.
Sandbox zombie survival game Project Zomboid will use Steam's servers, library, update system and DRM, but will not be appearing on the store itself for the forseeable future.
A look over the Greenlight project pages for McPixel and Dream No More Room in Hell show little movement, if any at all. Although some like feudal role-player Kenshi are still in development.